Microwave-assisted green synthesis of carbon dots derived from wild lemon (Citrus pennivesiculata) leaves as a fluorescent probe for tetracycline sensing in water

Herein, we report an eco-friendly biomass based completely greener microwave assisted synthesis of carbon dots from wild lemon leaves having superior photo-luminescent properties with moderately good quantum yield. The carbon dots synthesized (LLCDs) were characterized by high resolution transmission electron microscopy, fluorescent, UV-vis absorption, Fourier transform infrared and Raman spectroscopic techniques. The quenching of native fluorescence of LLCDs observed with tetracycline antibiotic was made use to make it as a fluorescent probe. Tetracycline is widely used as a drug to treat various bacterial infections and as a growth promoter in variety of farming fields like aquaculture and feedstock's. The excessive usage of this antibiotic in farming fields caused severe water pollution and micro level detection of tetracycline in water system is highly demanded for the protection of health and environment. Based on the selective interaction of tetracycline with LLCDs, a simple and cost effective analytical method was proposed to detect tetracycline in water with satisfactory parameters. The limit of detection is 0.42 µM with a linear range of 0 to 27. 27 µM. The mechanism of quenching was investigated through various experiments and finally accredited to static quenching. Furthermore, the same method has been practically applied for tetracycline detection in natural water resources with acceptable recoveries ranging from 95.56 % to 101.93 %.